Be aware at Epcot they do have you spend a good portion of your time- about half or a tad less than half learning how to ride and steer the Segway, along with basics like helmet, etc.
We did the Segway during the Flower and Garden Show at Epcot and it was a wonderful way to see all the countries in an hour. However, unless they have changed things you should note that they do not let you just "go free" all over the countries as the description of the tour might imply. There is a leader and a tail and you are suppose to stay in line. I wasn't interested in zigging and zagging, but wanted to see the flowers, so often I would wait as they did an exercise. They are very strict about rules. We had about 15 minutes of free time directly in the middle and for photos (which are wonderful to have them take) so be sure to bring your camera with you. I would also go early and when they call for the Princess Breakfast at the main gates (if you are going 1st thing in the morning) let them know you are there for the Segway Tour. If you are late beyond a certain point I dont think they let you enter the class.
Enjoy!